One can have remarkable control of the surface properties by patterning it to contain micro- and nanometer sized structures. In a femtosecond laser ablation those structures are produced with an very short laser pulses that enables precise controlled way to modify the surface topology.
With small structures one can control various functionalities including reflection of light, hydrophobicity, oleophobicity, and even the growth of biological material on the surface. Each functionality requires its own surface structure and proper chemical properties of the surface material. The femtosecond laser provides enough energy in each light pulse so that practically any material from stainless steel to biological tissues can be ablated.
Our team has developed the efficiency of the ablation process by introducing various ways to control the laser beam. These include, e.g., interferometric pattern in ablation and array of beams constructed with diffractive gratings. Also, we have worked successfully in the replication of the structures onto polymer surfaces.
- Prof. Pasi Vahimaa
- PhD Kimmo Päiväsaari
- PhD Martti Silvennoinen
- PhD Jarno Kaakkunen
More information about the research
Presentations in Sway
- Femtosecond laser ablation
- Super hydrophobic surfaces with a femtosecond laser
- Making glass hydrophobic
A spherical image of the femtosecond laser laboratory
Externally funded projects:
- FinFem: Nano structures and applications with fs laser technology, 2008-2010. Funded by Tekes, www.tekes.fi
- Multibeam: Multiple laser beam processing in mass production, 2011-2013. Funded by Tekes, www.tekes.fi
- Laser-ablation assisted spectroscopy the diagnostics of plants, 2014. Funded by Tekes/ERF, www.tekes.fi
Martti Silvennoinen, “Precise material processing with Spatial Light Modulator – controlled Femtosecond laser beam,” PhD thesis, University of Eastern Finland (2014). http://epublications.uef.fi/pub/urn_isbn_978-952-61-1541-2/
Jarno Kaakkunen, “Fabrication of functional surfaces using ultrashort laser pulse ablation,” PhD thesis, University of Eastern Finland (2011). http://epublications.uef.fi/pub/urn_isbn_978-952-61-0539-0/
M. Silvennoinen, J. J. J. Kaakkunen, K. Päiväsaari, and P. Vahimaa, ”Parallel femtosecond laser ablation with individual controlled intensity,” Optics Express, 22, 2603-2608 (2014).
K. L. Wlodarczyk, J. J. J. Kaakkunen, P. Vahimaa, and D. P. Hand, ”Efficient speckle-free laser marking using a spatial light modulator,” Applied Physics A, DOI 10.1007/s00339-013-8186-1 (2013)
M. Silvennoinen, J. J. J. Kaakkunen, K. Päiväsaari, and P. Vahimaa, ”Water spray assisted ultrashort laser pulse ablation,” Applied Surface Science, 265, 865-869 (2013).
M. Silvennoinen, J. J. J. Kaakkunen, K. Päiväsaari, and P. Vahimaa, ” Parallel microstructuring using femtosecond laser and spatial light modulator,” Physics Procedia, 41, 1875-3892 (2013).
T. Nuutinen, M. Silvennoinen, K. Päiväsaari, and P. Vahimaa, ”Control of cultured human cells with femtosecond laser ablated patterns on steel and plastic surfaces,” Biomedical Microdevices 15(2), 279-288 (2013).
J. J. J. Kaakkunen, M. Silvennoinen, K. Päiväsaari, and P. Vahimaa, ”Water-assisted femtosecond laser pulse ablation of high aspect ratio holes,” Physics Procedia, 12(2), 89-93 (2011).
J. J. J. Kaakkunen, K. Päiväsaari, and P. Vahimaa, ” Fabrication of large-area hole arrays using high-efficiency two-grating interference system and femtosecond laser ablation,” Applied Physics A – Materials Science & Processing, 103, 267-270 (2011).
M. Silvennoinen, J.J.J. Kaakkunen, K. Päiväsaari, P. Vahimaa, and T. Jääskeläinen, ”Controlling the hydrophopic properties of material using femtosecond ablations,” Journal of Laser Micro Nanoengineering, 5, 97-98 (2010).